As the most common form of arthritis, osteoarthritis (OA) affects nearly 21 million Americans. Marked by pain and inflammation caused by cartilage breakdown in various weight-bearing joints (e.g., knee), sufferers commonly treat their symptoms with over-the-counter or prescription medication. But relief can often be offset by side effects and complications, such as gastrointestinal upset, ulcers or worse.

Luckily, you can quell your joint pain and swelling with a number of natural alternatives that are easier to tolerate. Here is a short guide to six options.

Glucosamine (with Chondroitin)

How It Works: Supplements of glucosamine, which slows and may even prevent progression of joint changes that cause osteoarthritis, are derived from either the shells of crustaceans, or are manufactured from vegetable materials such as corn.

What the Science Says: Results from a 24-week study in the New England Journal of Medicine suggest that taking glucosamine and chondroitin together may help reduce pain in individuals with moderate-to-severe osteoarthritis; the combination didn’t seem to help those with mild symptoms, however. It may take several weeks to experience the full pain-relieving effects.

The Best Way to Use It: Use the recommended doses–1500mg daily for glucosamine sulfate or glucosamine hydrochloride and 800-1200mg daily of chondroitin sulfate. Also, go for quality. “The quality and biologic activity levels of chondroitin and glucosamine sources vary, and good products use the most active components. Many of the cheap brands contain inexpensive and often inactive chondroitin, for instance,” says Jason Theodosakis, MD, author of The Arthritis Cure and other books.

How It Works: Ginger contains active compounds that may decrease joint pain and inflammation in people with osteoarthritis and rheumatoid arthritis.

What the Science Says: Study findings from the University of Miami show that among 247 subjects, 63 percent of people taking 255mg of ginger extract twice daily reduced their OA knee pain. The ginger users were also able to reduce their need for “rescue” medication, namely acetaminophen.

The Best Way to Use It: Ginger is available in multiple forms, including capsules, extract and tincture. Follow dosage guidelines on the label or consult your doctor. You can also use ginger root to make a compress to apply directly to painful joints.

Caution: Talk to your doctor first if you are taking antacids and/or any medication for blood pressure, blood thinning, heart disease or diabetes–ginger could interact with these drugs.

How It Works: SAMe, a naturally occurring chemical in the body that is also available as a supplement, treats pain, stiffness and joint swelling, improves mobility, rebuilds cartilage; also used to treat depression, fibromyalgia and chronic fatigue syndrome.

What the Science Says: Findings to date indicate that SAMe relieves pain as well as nonsteroidal anti-inflammatory drugs but with fewer side effects.

The Best Way to Use It: The standard dosage is 600-1200mg daily for OA, best taken under a doctor’s supervision. Also, take on an empty stomach.

Product Example: Pretorius SAM-E Tablets.

MSM (Methylsulfonylmethane)

How It Works: MSM is an organic sulfur compound found naturally in fruits, vegetables, grains, animals and humans. “Sulfur is the third most common mineral in the body and is critical for the structure of connective tissues, including those in and around the joints,” says Theodosakis. MSM has an anti-inflammatory effect, and is believed to help repair damaged connective tissue associated with joint degeneration.

What the Science Says: A randomized, double-blind, placebo-controlled trial of 50 men and women, ages 40-76, with knee OA pain showed pain reduction and improved mobility after using MSM (3g, twice daily) for 12 weeks. “MSM became popular mostly through anecdote, but now the research is catching up,” says Theodosakis.

The Best Way to Use It: MSM is available in topical and oral forms. The typical oral dosage for OA is 1000-3000mg daily, with meals. To avoid minor gastrointestinal symptoms, try gradually increasing the dose. Follow label directions for topical forms.

Caution: If you are using any prescription or over-the-counter drugs, take several hours before or after taking MSM, as some drugs can bind with mineral-containing supplements. Theodosakis also recommends the American-made, distilled form of MSM; the Chinese version may not have the same quality standards or purity.